The invention relates to a package for metal-ceramic substrates consisting of a ceramic layer and a plurality of single metallizations or structured areas formed on at least one surface side of the ceramic layer. Between the structured areas, break-off lines are made into the ceramic layer.
Known in the art is the DCB (Direct Copper Bond) technology, which is used to bond metal layers or sheets (e.g. copper sheets or foils) with each other and/or with ceramic or ceramic layers, namely using metal or copper sheets or metal or copper foils, which are provided on their surfaces with a layer or coating (hot-melt layer) resulting from a chemical bond between the metal and a reactive gas, preferably oxygen. In this method, which is described for example in US-PS 37 44 120 and in DE-PS 23 19 854, this layer or coating (hot-melt layer) forms a eutectic with a melting temperature below the melting temperature of the metal (e.g. copper), so that the layers can be bonded to each other by placing the foil on the ceramic and heating all layers, namely by melting the metal or copper essentially only in the area of the hot-melt layer or oxide layer.
This DCB method then comprises for example the following steps:
Oxidation of a copper foil so as to produce an even copper oxide layer;
placing the copper foil on the ceramic layer;
heating the composite to a process temperature between approx. 1025 and 1083° C., e.g. to approx. 1071° C.; and then
cooling to room temperature.
Known in the art are metal-ceramic substrates, also large-surface metal-ceramic substrates or metal-ceramic substrates manufactured as multiple printed panels, as substrates or circuit boards for electric circuits or modules. These metal-ceramic substrates consist, for example, of a ceramic layer or of a relatively large-surface ceramic substrate, which is provided on at least one surface side with a metallization, for example, in the form of a copper foil using the DCB bonding method. The metallizations are structured to form single metallizations that are homogeneous. Between these single metallizations, break-off lines are made in the rectangular or square ceramic layer, on which the metal-ceramic substrate can be separated by breaking them into single substrates or single circuits or modules, preferably after being equipped with electric components. The break-off lines allow easy separation of the large-surface metal-ceramic substrate into single substrates, but also relatively easily result in accidental breakage of the metal-ceramic substrates, especially during transport.
Large-surface metal-ceramic substrates or metal-ceramic substrates manufactured as multiple printed panels according to the invention are understood to be such metal-ceramic substrates that have a format of 178 mm×127 mm or larger and on at least one surface side of the ceramic layer, but preferably on both surface sides of the ceramic layer have single metallizations, between which the break-off lines extend into the ceramic layer, so that by breaking along this break-off line the large-surface metal-ceramic substrate can be separated into single substrates, which respectively form components or the printed circuit board of a circuit or module.
It is an object of the invention is to present a package that enables the safe transport and storage of large-surface metal-ceramic substrates manufactured as multiple printed panels.
In a further embodiment of the invention the package is designed for example so that
the edge of the tray is embodied as a circumferential U-profile that is open toward the tray bottom side,
and/or
the at least one holder formed in the tray for holding at least one metal-ceramic substrate and adapted to the format of the metal-ceramic substrates has corner recesses,
and/or
projections are formed on the at least one wall circumferentially limiting the at least one holder and projecting into the holder, which (projections) form contact surfaces for the at least one metal-ceramic substrate and which define a partial space of the holder serving to accommodate this substrate,
and/or
the wall circumferentially limiting the at least one holder is inclined at least on partial areas, for example on the projections opposing the plane of a bottom of the at least one holder, namely so that the wall in this partial area, when the package is not closed, encloses an angle somewhat larger than 90°, for example an angle between 90 and 95°,
and/or
the tray is manufactured in one piece by deep drawing from a flat material, preferably from a plastic flat material, for example from a thermoplastic flat material,
and/or
the material of the tray, preferably the material used for the deep drawing, has a material thickness between 0.3 and 4 mm, preferably a material thickness of 1 mm,
and/or
when the package is closed, at least one tray with at least one metal-ceramic substrate in the at least one holder is accommodated in a vacuum-tight sealed and evacuated external package, namely preferably so that forces created by the external ambient or atmospheric pressure on the edge fix the at least one metal-ceramic substrate in the holder by circumferential clamping,
and/or
the external package or covering is made from a bag or hose of a preferably weldable flat material, for example from a weldable foil,
and/or
the interior of the sealed covering or external package is filled with a protective gas, preferably with nitrogen, namely preferably with a pressure that is below the ambient or atmospheric pressure,
and/or
the foil forming the covering or external package is provided with a diffusion barrier against moisture and/or oxygen,
the above characteristics of the package being able to be used singly or in any combination.
Further embodiments, advantages and possible applications of the invention are disclosed by the following description of exemplary embodiments and the drawings. All characteristics described and/or pictorially represented, alone or in any combination, are subject matter of the invention, regardless of their being summarized or referenced in the claims. The content of the claims is also included as part of the description.